Certain water heater appliances include a tank therein. Heating elements, such as gas burners, electric resistance elements, or induction elements, heat water within the tank during operation of such water heater appliances. In particular, the heating elements generally heat water within the tank to a predetermined temperature. The predetermined temperature is generally selected such that heated water within the tank is suitable for showering, washing hands, etc.
During operation, relatively cool water flows into the tank, and the heating elements operate to heat such water to the predetermined temperature. Temperature sensors are typically included in water heater appliances to, among other things, determine the temperature of the water in the tank. Many water heater appliances utilize multiple temperature sensors. However, a recent trend has been to utilize a single temperature sensor, to reduce the cost of the water heater appliance.
It is generally desirable to be able to detect flow events in a water heater appliance, when cool water is added to the water heater appliance due to, for example, the flow of heated water from the appliance for downstream use. It is also generally desirable to know the amount of water being added during a flow event. Recently, methods have been developed for utilizing temperature sensors to determine added water volume during a flow event. In general, temperature decay during a flow event is monitored. Algorithms have been developed which correspond the temperature decay to the added volume during the flow event. Such methods are disclosed, for example, in U.S. Patent Application Publication No. 2010/0206869 entitled “Heat Pump Water Heater Control”, U.S. Pat. No. 8,422,870 entitled “Residential Heat Pump Water Heater”, and U.S. Patent Application Publication No. 2012/0145095 entitled “Residential Heat Pump Water Heater”, all of which are incorporated by reference herein in their entireties.
However, in many cases, it may be difficult for temperature decay during a flow event to be monitored by a temperature sensor. Accordingly, improved water heater appliances are desired in the art. In particular, water heater appliances which provide improved temperature decay and flow event detection would be advantageous.